Prime Minister Tony Abbott has left open the possibility of sending more troops to Iraq, after Islamic State militants last week claimed the key city of Ramadi. But former Labor leader Mark Latham says Australia was wrong to commit troops to Iraq in 2003 and it shouldn’t be there now. Also in this edition of Between the Lines, Ireland’s overwhelming vote in favour of allowing same-sex marriage has emboldened supporters around the world, including in the United States, where gay marriage is now legal in 36 out of 50 states. Why is western public opinion shifting so quickly on same-sex marriage?